The National Weather Service continues the heat advisory through Tuesday afternoon. Temperatures once again on Tuesday will rise to the upper 90s however high humidity will make it feel like 105 to 110 degrees.
The Iowa Soybean Association has launched an informational campaign to help farmers deal with weeds that are becoming resistant to the farm chemicals commonly used to kill them.
Iowa State University agronomist Mike Owens says herbicide-resistant weeds are present in 20 to 30 percent of Iowa soybean fields, about 2 to 3 million acres and the area is likely to grow.
He says most farmers are just a year or two away from a serious weed control problem as each generation of seed becomes more resistant to weed killers used most often.
Strategies include rotating chemicals used from year to year, controlling weeds in waterways, edges and ditches, and increasing crop rotation to break weed cycles.